Chain grate stoker



Oct. 18, 1932.

H. J. KERR CHAIN GRKTE STOKER Filed lay 4. 1928 INVENTOR W m BY W ajay/y ATTORNEYS Patented Oct. 18, 1932 UNITED STATES ATENT OFFICE HOWARDJ. KERR, OF WESTFIELD, NEW JERSEY, ASSIGNOR TO THE BABCOCK & WILCOXCOMPANY, OF BAYONNE, NEW JERSEY, A CORPORATION OF NEW JERSEY CHAIN GRATESTOKER Application filed May 4, 1928.

This invention relates to a furnace that is provided. with a chain gratestoker operated under forced air blast in which provision is made forutilizing leakage air by conducting it to a portion of the grate andutilizing it I for combustion purposes. The invention will be understoodfrom the description in connection with the accompanying drawingin whichFig. 1 is a section through an illus- {I} trative embodiment of theinvention taken along the line 11 of 2, and Fig. 2 is a longitudinalvertical section taken along the line 22 of Fig. 1. In the drawingreference character 1 indicates a furnace that is provided with a fuelhopper 2 with an opening 3 at the bottom thereof for feeding a layer ofcoal of proper thickness onto the upper run 1 of a chain grate. Thelower run of the chain grate is indicated at 5 and the chain passesaround rollers 6 and 7 at opposite ends of the stoker which may bedriven in any convenient manner.

Cross members or partition plates 8 in the form of I-beams extendlaterally across the stoker and in conjunction with plates 8c extendingtherebetween provide boxes or compartments 9, 10, 11 and 12 beneath theupper run 4 of the chain grate. Another compartment 13 is arrangedalongside the compartment 12 and formed by the I-beams 8 in conjunctionwith partition 8 and seals 13a and 30 located along the upper side ofthe lower run 5 of the chain grate. Seals 8 are provided at the upperends of the I-beams 8 to prevent air from passing from one compartmentto the other. An I-beam 13 passes longitudinally through the stokerbetween the upper and lower runs of the chain grate dividing the stokerinto two similar parts. A series of ducts 14 and 15 are provided at thesides of the stoker and dampers 16 and 17 in these ducts, operated byhandles 18 and 19, control the amount of air passing through the ductsinto the respective compartments 9 to 13, by way of the openings 20 to24 on opposite sides of the stoker which lead to the compartments 9 to13, respectively. The plates 8a are arranged to provide V-shaped bottomsfor the compartments and screw conveyors 25 are located at the bottom ofthe Serial No. 275,009.

compartments to remove the siftings that may fall through the upper run4 of the chain grate into these compartments.

A drag plate 26 is provided below the lower run 5 of the chain grate andis supported upon I-beams 26. A damper 27 operated by a handle 27 isprovided in the floor of the compartment 12. A wall or partition 8extends from the partition plate 8 at the ri ht hand end of compartment12 (Fig. 2) to the seal 30 located along the upper side of the lower run5 of the chain grate, and a damper 28 operated by a handle 28 isprovided in this wall or partition 8", to control the amount of airadmitted to compartment 13 through an opening in said partition. An airtight casing 31 is provided at the front end of the stoker below thecoal hopper 2.

The operation is as follows: The dampers 16 are regulated so as to havethe highest pressure in the compartment 9 and lower pressures in thesucceeding compartments, or the pressures in the compartments may beregulated in any other convenient manner. Air that leaks from the firstcompartment past the links of the chain and the first seal, as indicatedby the front arrow, )asses to the space 32 and then to the space betweenthe bottoms of the boxes or compartments and the drag plate of thestoker. This air may be permitted to pass into the compartment 12 byopening the damper 27 or into another compartment 13 below the righthand end of the upper run of the chain grate 4 by opening the damper 28,or both, so that air that has leaked from the first compartment passesthrough the fuel bed where the fuel has become thin due to combustion.The siftings that fall through the upper run of the chain grate near itsrear end are carried by the lower run of the grate along the drag plate26 and discharged into the opening provided for the siftings at the lefthand end of this drag plate;

Air is usually heated before it is fed to a stoker for combustionpurposes, and if leakage air is not recovered in some such way asdescribed above, the heat would be wasted so that a decided economy iseffected by thi. invention. Leakage from the front compartlnent wouldordinarily pass to waste outside of the furnace and as this pressure isin most instances higher than at some succeeding point, the leakage aircan be returned by utilizing pressure differences to a con1partment inwhich the pressure is lower.

I claim:

1. In a furnace, a chain grate stoker, a plurality of air compartmentshaving air inlets formed beneath the upper run of said stoker, and meansbetween the lower run of said stoker and said compartments to conveylea-kage air from a compartment disposed towards the forward part ofsaid furnace to a compartment disposed towards the rear thereof.

2. In a furnace, a chain grate Stoker, a plurality of air compartmentshaving air inlets formed beneath the upper run of said seeker, meansbetween the lower run of said stoker and said compartments to conveyleakage air from a compartment disposed towards the forward part of saidfurnace to a compartment disposed towards the rear thereof, and meansassociated with said rear compartment to control the amount of leakageair admitted thereto.

3. In a furnace, a chain grate stoker having a plurality of compartmentsformed elow and opening through the upper run thereof, means forsupplying air under different pressures to different compartments, andmeans for conducting leakage air from one compartment to anothercompartment under a lower pressure.

4. In a furnace, a chain grate stoker having compartments formed betweenthe upper and lower runs thereof and opening through the upper runthereof, means for supplying air under different pressures to successivecompartments of said stoker, and means for conducting leakage air fromone compartment to a non-adj acent compartment under a lower pressure.

5. In a furnace, a chain grate stoker having compartments formed betweenthe upper and lower runs thereof and opening through the upper runthereof, means for supplying air under different pressures to differentcompartments, and means for conducting leakage air from a frontcompartment to a rear compartment under a lower pressure.

6. In a furnace, a chain grate stoker having compartments formed betweenthe upper and lower runs thereof and opening through the upper runthereof, means for supplying air under difierent pressures todifferentcompartments, and means for conducting leakage air from acompartment adjacent the front end of said stoker longitudinally belowsaid compartments to a compartment under a lower pressure, said meansincluding a damp or controlled air inlet to said low pressurecompartment.

7 In a furnace, a chain grate stoker having compartments formed betweenthe upper and lower runs thereof and opening through the upper runthereof, means forming an air-tight chamber at the front of said Stoker,means for supplying air at different pressures to different compartmentsof said stok er, and means for conducting air leaking into said frontchamber to a rear compartment under a lower pressure.

8. In a furnace, a chain grate stoker having side-by-side compartmentsformed between the upper and lower runs thereof and opening through theupper run thereof, means forming an airtight chamber in front of saidcompartments, a drag plate below said lower run and spaced from thebottoms of said compartments, means for supplying air under differentpressures to different conipartments, and means for conducting airleaking into said front chamber through the space between the bottoms ofsaid compartments and said drag plate to a compartment under a lowerpressure adjacent the rear end of said stoker.

HOWARD J. KERR.

